In modern minimally invasive surgery, instruments necessary for an operation are introduced into the abdominal cavity through one or several cannulae (trocar sleeves) and guided under the control of an endoscope, which has likewise been introduced into the abdominal cavity. Surgical areas are sometimes cared for by means of intraabdominal ligatures, for example by an Endoloop.TM. ligature with a slip knot. These are introduced with a tubular applicator into the area which is to be ligated, and are placed around the graspable stump of a hollow organ or of a bundle of vessels. The loop is pulled tightly outside the body, or closed with a ligature clip. The endoscopically monitored placement of such an endoligature loop calls for great manual dexterity and is also possible only with freely graspable vessel stumps. End-to-end anastomosis of hollow organs in laparoscopic operation techniques pose additional concerns. For instance, in open surgery, a purse-string suture must be applied if an end-to-end anastomosis is to be performed with a circular stapling device. Known from WO90/06725 is a laparoscopic instrument for the application of endoligatures and for the looping about of hollow organs, which instrument is introducible into the abdominal area through a cannula. This instrument has an instrument tube containing a ligature on the distal end of the headpiece. The headpiece is provide with a continuous channel which runs in the longitudinal direction of the instrument tube. A belt-like, loop-shaped continuation connects with the distal end of the headpiece. The free end of the continuation is grasped by the operator by means of an additional auxiliary aid, laid about the organ to be tied off and introduced into the channel. The free end of the belt-like continuation and the channel are provided with notched surfaces which correspond to each other. In the inside of the instrument tube, the free end can be grasped by a gripping tool, which tool is movable in the longitudinal direction, so that the ligature binder may be pulled tight. The notched surfaces prevent a release or loosening of the connection.
A drawback of this previously known laparoscopic instrument is that, upon introduction into the headpiece, the free end of the belt-like continuation forms an acute angle in the area where the belt-like continuation adjoins the headpiece. As a result, the shaped of the loop differs markedly from the ideally circular shape to be placed around the organ. It is awkward for the operator to have to pull the end of the actuation rod, which is coupled to the gripping tool, along the full length of the instrument tube through which the ligature binder is tightened.